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Akhilesh_128432's avatar
Akhilesh_128432
Icon for Nimbostratus rankNimbostratus
Feb 12, 2016

Irule not working for Cookie Persistence

Hi Team,

 

We have one application and can be accessed via F5 successfully and we are using cookie persistence for that. Now we are trying to access through Mobile devices. Since there is no cookie for mobile, I wrote a Irule for this.

 

I created a universal persistence for this Virtual server and applied following Irule for this,.Now Mobile traffic is working fine but I am not sure how to add insert cookie for my Browser traffic (else condition in my loop). I tried different option and none of them are working. Can anybody help me on this

 

when HTTP_REQUEST {

 

log "MA Testing : Requested from IP [IP::client_addr]"

set cid [findstr [HTTP::uri] "contextId" 10 "&"] if { $cid != "" } {

 

log "\MA Testing : ContextId found. Persist based on contextid : $cid"

persist uie $cid

 

log "MA Testing: Pool member [LB::server name] was selected"

} else

 

log "\MA Testing : No context id found. So persist based on Session id in the cookie"

persist uie cookie

 

log "MA Testing: Pool member [LB::server name] was selected"

} }

 

application delivery
cookie persistence
iRules
LTM

1 Reply

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  • Kai_Wilke's avatar
    Kai_Wilke
    Icon for MVP rankMVP
    Feb 12, 2016

    Hi Akhilesh,

    the command 

    [persist uie cookie]
    does not set/read any kind of HTTP cookies, its more or less just tracking your session persistence using the static plain-text value "
    cookie
    ".

    To understand the 

    [persist uie]
    behavior, you have to read the command like 
    [persist uie UNIVERSAL_TXT_STRING_TO_TRACK]
    , where the string can be any kind of information the user would provide while requesting information. It could be a source IP, it could be an URI, it could be an HTTP-Header or HTTP-Cookie value the user is providing on each single request. Well, in your specific case, you're not using any provided data, instead your using the fixed value of "cookie" for every client causing to team every session to the same pool_member...

    To track your users based on a HTTP-Cookie value using 

    [persist uie]
    your need to monitor the 
    HTTP_REQUEST
    for the desired HTTP-Cookie value. If the value is present, then 
    [persist uie $cookie_value]
    the session. If the user is not providing the desired cookie, then perform a regular load-balacing decission (e.g. Round-Robin) and monitor the 
    HTTP_RESPONSE
    if the server sets the cookie. As soon the server is setting the Cookie, issue a 
    [persist add uie $cookie_value]
    to team the cookie value to the current pool_member selection. The very next REQUEST of the user would then provide the 
    $cookie_value
    which can be used to 
    [persist uie $cookie_value]
    the request to the last pool_member selection.

    Alternativly you could also use the 

    [persist cookie insert MY_LB_COOKIE_NAME]
    command, to let the F5 insert an auto-generated cookie used exclusivly for persisting the session. Its a much easier syntax and does not require any well known application cookies to be in place. In addition to that its completely stateless and therefor doesn't consume session table memory to store the persitence information...

    Cheers, Kai